1. Field
Embodiments of the present invention relate to a vehicle driving force transmission structure in a power unit having an auxiliary transmission of a separate body.
2. Description of Related Art
As a vehicle driving force transmission structure, a vehicle driving force transmission structure is disclosed, for example, in Patent Document 1 (Japanese Patent No. 3845155 (FIGS. 9 and 9)). In the structure, a main transmission having a multi-speed transmission mechanism and so forth and an auxiliary transmission having a forward-reverse switching mechanism and so forth are accommodated in the inside of a crankcase of an internal combustion engine which forms a power unit. Another vehicle driving force transmission structure is disclosed, for example, in Patent Document 2 (Japanese Laid-Open No. 2010-242829 (FIGS. 1 and 2)), which includes an auxiliary transmission of a separate body directly coupled to a crankcase in which a main transmission is accommodated.
Where an auxiliary transmission is provided as a separate body from an internal combustion engine, even if the internal combustion engine itself can be formed in a reduced size, where both transmissions are joined together, there is the possibility that the size may become great. Therefore, further miniaturization of a power unit having an auxiliary transmission is demanded.